Ya it will either eat if HP is too low or when it needs to boost agility lvl to enter the course
Like if you are doing ardy course at lvl 87 it will keep your agiliy lvl at 90
Summer pies have nothing to do with run energy in the script, it's to boost your agility level 5 levels
You don;t need staminas on rooftops, just a few pieces of gracefull and you never run out of energy
Mirror is generally speaking always slower than stealth and less accurate, especially for the wave detection.
Fast paced minigames will have extra delays on mirror unfortunately. try on stealth and you will see the difference